Verify if removeDecorators transform is needed with Ivy

[filipesilva]

For a given service, Ivy outputs this:

import { Injectable } from '@angular/core';
import * as i0 from "@angular/core";
var bigDependencyLoader = function () { return import(/* webpackChunkName: "big-dependency" */ '../lorem/big-dependency'); };
var LoremService = /** @class */ (function () {
    function LoremService() {
    }
    LoremService.prototype.load = function (options) {
        return bigDependencyLoader().then(function (m) { return new m.BigDependency().setOptions(options); });
    };
    LoremService.ɵfac = function LoremService_Factory(t) { return new (t || LoremService)(); };
    LoremService.ɵprov = i0.ɵɵdefineInjectable({ token: LoremService, factory: function (t) { return LoremService.ɵfac(t); }, providedIn: 'root' 
});
    return LoremService;
}());
export { LoremService };
/*@__PURE__*/ i0.ɵsetClassMetadata(LoremService, [{
        type: Injectable,
        args: [{ providedIn: 'root' }]
    }], null, null);

and VE outputs this:

import { __decorate } from "tslib";
import { Injectable } from '@angular/core';
import * as i0 from "@angular/core";
var bigDependencyLoader = function () { return import(/* webpackChunkName: "big-dependency" */ '../lorem/big-dependency'); };
var ɵ0 = bigDependencyLoader;
var LoremService = /** @class */ (function () {
    function LoremService() {
    }
    LoremService.prototype.load = function (options) {
        return bigDependencyLoader().then(function (m) { return new m.BigDependency().setOptions(options); });
    };
    LoremService.ɵprov = i0.ɵɵdefineInjectable({ factory: function LoremService_Factory() { return new LoremService(); }, token: LoremService, providedIn: "root" });
    LoremService = __decorate([
        Injectable({ providedIn: 'root' })
    ], LoremService);
    return LoremService;
}());
export { LoremService };
export { ɵ0 };

The CLI actually has a dedicated pass to remove the __decorate call in https://github.com/angular/angular-cli/blob/master/packages/ngtools/webpack/src/transformers/remove_decorators.ts.

If it's not needed in Ivy, we could disable that pass for faster builds and rebuilds.

[filipesilva]

@alxhub confirmed that this is still needed, ngcc removes the top-level decorators, but not the rest of the metadata (inputs, ctor parameters, etc).

[filipesilva]

I misunderstood actually, I thought that comment was about the app compile but it was ngcc.

@alxhub says:

In the app compile, Ivy completely removes the decorators afaik.

So we should be ok to not run this transform on Ivy apps.